Curiosity celebrates ten years on Mars

Curiosity's location in Gale Crater

Sometime today the rover Curiosity will celebrate its tenth anniversary on Mars. The oblique graphic of Gale Crater above, first released by the science team shortly before landing in 2012, has been further annotated with a red line to show the rover’s journey since then. As noted by Scott VanBommel, Planetary Scientist at Washington University, today on the science team’s blog:

As we the science and engineering teams have aged this last decade, so has Curiosity. The toll of ten years and nearly 28.5 km [17.7 miles] of Mars driving shows with every MAHLI wheel imaging activity, with less energy available for a plan, and with aging mechanisms. This is the life of a Mars rover. Spirit and Opportunity were no different, yet they persisted and paved the way scientifically and technologically for the rovers of today. Curiosity has made numerous scientific discoveries during these ten years, emphasized by the over 500 science team publications, with many more ahead as we continue our ascent and exploration of Gale crater and Mount Sharp.

I look forward to the next ten years.

Despite that aging, Curiosity’s general condition appears quite excellent, with its wheels the greatest concern but generally holding up. Based on the last ten years, the rover is likely to remain operational for at least ten more years, if not longer.

In the more immediate future, the rover is only days away from getting its first good look down into Gediz Valles, that canyon on the graphic above that it has been traveling towards since day one.

A good review of five of Curiosity’s biggest discoveries using its sample analysis instrument can be found here.

Curiosity heads into the pass

Mosaic by Curiosity
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Overview map
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Cool image time! The mosaic above, cropped, reduced, and annotated to post here, was created from 31 navigation images taken by the Mars rover Curiosity, and shows the rover’s upcoming drive. From the science team’s July 29, 2022 update:

We are attempting to reach a high point, just at the top right edge of the image, so we can look down into the valley to see if there is a way out on the other side and to help plan our path forward. High tilts, sand, and large and small rocks clutter the terrain, requiring the Rover Planners to pick their way around while making sure they stay clear of the hazards.

After the drive, we took a lot of imaging from our new location, including a 360 degree Mastcam mosaic and an upper tier of imaging to catch the tall relief of the valley walls.

The green dot in the image above as well as the overview map to the right indicates the approximate location on the cliff face of a previously observed recurring slope lineae, streaks that appear to come and go seasonally whose origin is still not understood.

The blue dot on the map marks the rover’s position on August 1, 2022. The yellow lines indicate the approximate area covered by the mosaic above. The large red dots on the overview indicate the rover’s original planned route, with the smaller red dots indicating the hoped-for route to get back to that path.

In the far distance the upper slopes of Mount Sharp can faintly be seen through the winter dust haze. That mountain is about 18,000 feet high, though its actual peak is not yet visible. Curiosity is still about 16,000 feet below that peak. Kukenan is about 1,500 feet high. The cliff with the slope lineae is probably about 400-500 feet high The two side hills that delineate the pass ahead are probably no more than 200 feet high.

Curiosity looks ahead

Curiosity looks ahead
Click for full resolution. For original images go here and here.

Overview map
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Cool image time! The panorama above, taken by one of the navigation cameras on the Mars rover Curiosity on July 23, 2022, forms a nice bookend to yesterday’s panorama. Yesterday Curiosity looked back at its past travels. Today it looks forward at where it is almost certainly heading in the days ahead.

On the overview map to the right, the yellow lines indicate the approximate area viewed by the panorama. The large red dotted line marks the rover’s original planned route, abandoned when the science team found the terrain on the Greenheugh Pediment too rough for Curiosity’s wheels. The smaller red dotted line is my present guess as to the rover’s future route to get back on course.

The flat-topped mountain dubbed Kukenán by the science team has probably been one of the prime goals of the entire mission, from the beginning. Its almost vertical face has innumerable layers, all of which record in great detail the geological history of Mars and Gale Crater. As noted by Abigail Fraeman from the Jet Propulsion Laboratory on June 30, 2022:

Kukenán’s Earth namesake is a tepui, or distinctive isolated table-top mountain, found in South America. The Martian Kukenán is also somewhat flat topped and an impressive expression in Mt. Sharp’s topography. While it looks like it’s about the same size as the hills that bound it in the above Navcam image (“Deepdale” on the left and the edge of “Bolivar” on the right), this effect is just due to forced perspective. In reality, Kukenán is nearly five times farther away and over three times as tall as Deepdale! Curiosity’s strategic traverse path takes the rover right past Kukenán in about a kilometer or so, so this feature will become a familiar landmark rising in our windshield for months to come.

The science team will likely park Curiosity in the saddle of the gap ahead for at least a week and spend a lot of time documenting that cliff face with multiple cameras, since at this location the rover will have an excellent view of that entire face. As it gets closer the angle looking up will get steeper, thus making viewing of the upper layers more difficult.

Curiosity looks back

Curiosity looks back
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Overview
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Cool image time! Normally I’d be hiking today, but since it is raining in southern Arizona at every mountain location we might want to go, I am forced to imagine hiking on Mars instead. The photo above, cropped to post here, was part of a mosaic of images taken on July 22, 2022 by the right navigation camera on the rover Curiosity.

Curiosity had just completed several drives that had it skirt around those two boulders visible in the center of the picture, as shown in the inset in the overview map to the right. The yellow lines indicate the approximate area covered by the photo. The blue dot marks Curiosity’s present location. The larger red dotted line the rover’s original planned route, with the smaller dotted line my guess as to the route the science team now plans to take to return to that course.

The rim of Gale Crater can be seen in the far distance, about 20 to 30 miles away and largely obscured by the winter dust that presently fills the atmosphere.

The science team had hoped to get close enough to these two boulders to touch them with the rover’s instruments, but decided to keep away because of both appeared a bit unstable.

More lacy Martian rocks

lacy Martian rock
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Cool image time! Because the Curiosity team is presently conducting a drilling campaign at its present position in the lower mountains of Gale Crater, the rover has not moved in the past few weeks. At these times, the science team also has the rover’s other cameras do extensive surveys of the surrounding terrain, including high resolution mosaics by its high resolution camera.

To the right is one photo from the most recent mosaic, cropped to post here. It was taken on July 10, 2022, and shows one many layered rock on the ground near the rover. Though no scale is provided, I suspect the extended flake from this rock is somewhere between six to twelve inches long.

Another illustration of the alien nature of Mars. This flake could not exist on Earth, where the heavier gravity and atmosphere would have acted to break it.

The new damage on Curiosity’s wheels

Comparing a Curiosity wheel from January to June 2022
To see the original images, go here and here.

On June 23, 2022 the Curiosity team provided a major update on the rover’s status on Mars, noting that because of new damage discovered on one of wheels, they were increasing the frequency of their wheel checks from once every 1000 meters of travel to once every 500 meters.

The team discovered that the left middle wheel had damaged one of its grousers, the zig-zagging treads along Curiosity’s wheels. This particular wheel already had four broken grousers, so now five of its 19 grousers are broken.

The previously damaged grousers attracted attention online recently because some of the metal “skin” between them appears to have fallen out of the wheel in the past few months, leaving a gap.

The photo comparison to the right might be showing that specific wheel, or not. The top image was taken January 11, 2022, and when compared then with an image taken six months earlier showed little change. Thus, in January 2022 it seemed the wheels were holding up well as Curiosity traveled into the mountains.

The new image at the bottom, taken June 3, 2022, shows new damage (as indicated by the plus sign) which had occurred sometime in the past six months. During that time the rover had attempted to cross the incredibly rough ground of the Greenheugh Pediment, and had been forced to retreat because the ground was too rough.

This most recent wheel survey in June thus confirms that the decision to retreat was a wise one. It appears that while the rover’s wheels can take the general roughness of the terrain in the foothills of Mount Sharp, the Greenheugh Pediment was beyond the wheels’ capabilities.

A major update from Curiosity’s science team

Panorama of Mars
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layered flaky rocks
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In a press release today, the Curiosity science team provided a major update on the rover’s recent travels in the mountain foothills of Gale Crater.

First and foremost was the new information about the rover’s wheels, which was buried near the bottom of the release:

The rover’s aluminum wheels are … showing signs of wear. On June 4, the engineering team commanded Curiosity to take new pictures of its wheels – something it had been doing every 3,281 feet (1,000 meters) to check their overall health. The team discovered that the left middle wheel had damaged one of its grousers, the zig-zagging treads along Curiosity’s wheels. This particular wheel already had four broken grousers, so now five of its 19 grousers are broken.

The previously damaged grousers attracted attention online recently because some of the metal “skin” between them appears to have fallen out of the wheel in the past few months, leaving a gap.

The team has decided to increase its wheel imaging to every 1,640 feet (500 meters) – a return to the original cadence. A traction control algorithm had slowed wheel wear enough to justify increasing the distance between imaging.

» Read more

Martian mountains, near and far

Navigation image
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Martian mountains, near and far
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Cool image time! The photo to the right, taken on June 18, 2022 by high resolution camera on the Mars rover Curiosity, provides a close-up of the area indicated by the arrow in the navigation camera image above taken three days earlier.

Because the rover had moved uphill slightly during those three days, the close-up can peek over what was the most distant ridge to see farther up Mount Sharp. (For context take a look at the overview map here.) All told, this close-up to the right shows four mountain ridges/ranges. First we have the ridgeline to the right, partly in shadow, which forms the right wall of the saddle that Curiosity appears heading for. Next we can see to the left the top section of the large 1,500 foot high mesa on the other side of the canyon Gediz Vallis. Note its many layers, all of which are going to become a major item of study as Curiosity gets closer.

Third we have a very rough and tumbled ridgeline, formed in a layer the geologists have dubbed the sulfate bearing unit. This layer tends to be very light in color, and more easily eroded. Curiosity is presently beginning to move into this layer as it climbs.

Finally there is the most distant ridge, which is simply the higher reaches of Mount Sharp though not its peak by a long shot.

The dusty winter air is quite evident by the chariscuro effect, causing the more distant ridges to appear more faded.

Note: This will be the first of three cool Martian images today. Stay tuned.

Rock growths on Mars!

Rock growths on Mars!
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Cool image time! The photo to the right was taken by the high resolution camera on the Mars rover Curiosity on May 15, 2022, and shows several incredibly strange vertical fingers of rock that appear to grow out of the ground. From the caption:

These likely formed as groundwater trickled through rock in the ancient past, depositing mineral cements over time; many years later, when the rock was exposed to the atmosphere, wind eroded the softer material around the cemented portions.

This formation explanation of course is only an educated guess. There are other possibilities, suggested by how cave formations grow over time, that are less likely but still must be considered. For example, maybe we are looking at a feature that grew upward as condensation from Mars’ once thicker and wetter atmosphere deposited new material on it over time.

Unfortunately, the image release does not provide a scale. My guess is that the longest finger is between six to twelve inches long, but it could be much smaller.

Curiosity: Into the mountains

Panorama on Mars, June 15, 2022
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Overview map
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Cool image time! The journey of Curiosity into the mountains of Gale Crater continues. The photo above, taken on June 15, 2022 by the rover’s left navigation camera, looks straight ahead at one possible route into those mountains.

The blue dot on the overview map to the right indicates Curiosity’s position. The yellow lines show the approximate area covered by the photo, by my estimate. The recurring slope lineae is a streak that comes and goes seasonally, and could be caused by some form of seepage. The marker layer, as indicated by the arrows, is a geological layer found at about the same elevation in many places on the flanks of Mount Sharp.

The red dotted line indicates the planned route of Curiosity, which it is presently striving to return to, having been forced to retreat from the Greenheugh Pediment because of its too-rough terrain.

For scale, Navarro Mountain is estimated to be about 450 feet high. Thus, the peak in the center of the panorama, which I think is the large mesa in the lower right corner of the overview map, is probably twice that height, about 1,500 to 1,700 feet high, and much higher than the two mesas that frame it on either side. Distance and perspective hide this difference.

When Curiosity finally gets inside Gediz Vallis and close to the side of that many-layered mesa, the view should be unbelievably amazing.

The science team has not yet revealed the precise route they plan to take to return to the planned route. While they may aim straight over the saddle in the photo above, I suspect they will instead bear west, following ground that is less steep.

Dusty Gale Crater in the winter

Curiosity's view to the north, May 25, 2022
Click on image for full resolution panorama. For original photos, go here, here, here, here, and here.

Overview map
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Cool image time! The panorama above, created from five images taken by Curiosity’s left navigation camera on May 25, 2022, looks north across the floor of Gale Crater at its rim about 25 miles away.

The butte on the left I think (though I am not certain) is the backside of the same butte seen from the front in December 2021. Then, Curiosity was below it looking up. Now, Curiosity is above it looking down.

For scale, that butte is about ten feet high. Navarro Mountain on the right is about 450 feet high, but looks less impressive because it is farther away.

It is now winter in Gale Crater, a time period when there is more dust in the atmosphere. This fact becomes very evident if you compare this panorama with a similar one taken in December 2021 in the Martian fall. Then, the air is crystal clear, and the rim can be seen in great detail. Now, though visible (barely) on the left, the haze makes the more distant peaks on the right almost invisible.

Curiosity has climbed about 1,750 feet since it landed in 2012. It is still about 12,600 feet below the peak of Mount Sharp. The blue dot and yellow lines in the overview map to the right indicates Curiosity’s location when the panorama was taken, and the approximate area covered by it.

Be sure and look at the full resolution panorama, especially the section near the middle, where the dramatic nature of this terrain is most evident.

Close-up on another flaky Martian rock

Close-up on another flaky Martian rock
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Overview map
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Cool image time! The picture above, reduced to post here, was taken by Curiosity’s high resolution camera on June 5, 2022 (sol 3494). It shows a close up of another flaky rock near where the rover is presently sitting (the blue dot on the map to the right), similar to the one that I highlighted on May 28, 2022 but zoomed in closer.

Not only can you seen the layered flakes extending out from the rock’s main body, you can see what appear to be small deposits of material between the flakes, as if at one point the material was being placed here by condensation, either from the atmosphere or liquid.

The curvy rounded edges of the rock’s larger flakes could have been caused by the same process, or by long slow wind erosion over the eons since the flakes were formed.

The photo appears to be part of a larger mosaic that the rover’s science team is having the camera take of the strange geology that now surrounds Curiosity. The science team also appears to be continuing its beeline south towards the rover’s original planned route, indicated by the red dotted line on the map. The green dot marks the approximate location of a seasonal recurring dark streak on the cliffside, suggesting some form of seepage, while the white arrows mark a distinct layer that scientists have identified in many places on the flanks of Mount Sharp.

Curiosity on a steep slope

null
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Overview map
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Cool image time! The panorama above, cropped, reduced, and enhanced to post here, was compiled from 29 photos taken on May 31, 2022 by the right navigation camera on the Mars rover Curiosity. It shows the steepness of the slope that the rover ended up parking on yesterday after it completed its drive. As noted in today’s rover update by Abigail Fraeman, Planetary Geologist at NASA’s Jet Propulsion Laboratory:

Curiosity starts the plan parked at an impressive 17˚ pitch (front up) and 17˚ roll (left up) for a total 24˚ tilt. You can get a bit of a sense of the rover’s non-horizontal position by looking at its orientation with respect to the ground in the above Navcam mosaic. Even though this slope is getting close to the limit of what Curiosity can traverse, we don’t think we’ll have any problems unstowing the arm or driving the rest of the way to the top because of the terrain we’re on – nice smooth bedrock with only a thin sand cover is almost the Martian equivalent of a paved road.

On the far right of the image you can also see Curiosity’s tracks. The rover had first approached this slope about 80 feet to the west, then backed off slightly to parallel the slope as it came east and then turned uphill. In the far far distance can be seen the rim of Gale Crater, about about 30 miles away and obscured by the atmosphere’s winter dust.

The overview map above shows Curiosity’s location with the blue dot. The approximate area covered by the section of the panorama above is indicated by the yellow lines. The red dotted line shows the rover’s original planned route. The white arrows indicate what the scientists have dubbed the “marker horizon,” a distinct layer found in many places on the flanks of Mount Sharp that they are very eager to study up close. The green dot marks the approximate location of a recurring slope lineae, a place where the cliff is seasonally darkened by a streak that appears each spring and then fades.

Flaky Martian rock

Flaky Martian rock
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Overview map
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Cool image time! The photo to the right, reduced and enhanced to post here, was taken on May 15, 2022 (sol 3474) by the high resolution camera on the Mars rover Curiosity, and shows a rock that was near the rover at that time that I estimate to be around three to four feet long.

This picture was taken the same day Curiosity also took a panorama and close-up images of a row of teeth-like boulders that sat a short distance in front of the rover. Those rocks, much larger than the one to the right, had numerous large flakes protruding from their sides.

This smaller rock has even more such flakes, all much smaller and clearly more delicate.

The overview map to the right shows Curiosity’s present position with the blue dot. The yellow dot marks where it was when it took this photograph. The red dotted line shows the rover’s original planned route. The white arrows indicate what the scientists have dubbed the “marker horizon,” a distinct layer found in many places on the flanks of Mount Sharp that they are very eager to study up close.

The green dot marks the approximate location of a recurring slope lineae, a place where the cliff is seasonally darkened by a streak that appears each spring and then fades.

The two orange dotted lines are my guesses for the two possible routes the rover will take from here to get back to its planned route, abandoned in mid-April when the Greenheugh Pediment was found too rough for Curiosity’s wheels. Though science team has not published a new route, the direction traveled in recent weeks suggests these are the possibilities. If I had to choose, I would favor the east route, as it bypasses more completely the pediment with its rough terrain.

The tuffy ground in the foothills of Mount Sharp

Shelfstone on Mars?
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Cool image time! The photo to the right, reduced and enhanced to post here, was taken on May 13, 2022 by the high resolution camera on the rover Curiosity, looking down at some of the unusual features on the ground near the rover.

The lighter circular feature in the center is not natural, but created by Curiosity’s Dust Removal Tool (DRT). As explained on May 16th on the science team’s blog:

When that dust settles on rocks, it can partially mask the chemistry and surface texture of these rocks from APXS and MAHLI in particular [two other Curiosity instruments]. Brushing rock surfaces with the DRT is not always possible, but it does improve scientific assessments of these surfaces.

What attracted me to this photo was the tuff-like look of that uplifted flat rock. It looks just like many surfaces one sees in a cave, where the surface gets covered with calcite flowstone or popcorn, due to either water flow or condensation and then evaporation of calcite-saturated water on the surface. In this case the cave formation this flat rock most resembles visually is shelfstone, though the formation process and chemistry was certainly different. It does suggest strongly however that some form of water process occurred here.

Pointy rocks on Mars

Pointy rocks as seen by Curiosity
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Pointy rocks as seen by Perseverance
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We have two cool images today from both of America’s rovers on Mars, each of which illustrates the alien nature of the red planet.

First on the right, cropped, reduced, and sharpened to post here, is a close-up taken by Curiosity’s high resolution camera on May 14, 2022 of the rightmost jagged boulder in yesterday’s navigation panorama. The number of layers is astonishing, though hardly a unique phenomenon as seen by Curiosity in its travels. Each likely marks one of many climate and geological cycles, each laying down another unique stratum for a relatively short period of geological time. Some might be volcanic ash or lava layers. Some might be layers caused by climatic changes.

The ability of these thin layers to extend outward so much, almost like they were floating, illustrates the weak Martian gravity, as well as the thinness of its atmosphere. On Earth, if the wind and weather didn’t cause these flakes to break, the gravity would.

Second on the right, cropped and sharpened to post here, is a high resolution photo taken by Perseverance on May 15, 2022 of one of the cliff faces seen by the rover looking up into the delta in Jezero Crater. Here again we see many layers and jagged, pointy rocks, illustrating again the many cycles in the past that formed the delta as it flowed into the crater.

The smoothness on the surface of the leftmost pointy rock suggests that it has stood in this position for a long very time, allowing the wind of Mars’ very thin atmosphere to erode its rough surface.

Curiosity climbs on!

Curiosity's view to the southeast, May 15, 2022 (Sol 3474)
Click for full resolution. Original images can be found here, here, and here.

Overview map
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Cool image time! The panorama above, created from three photos taken on May 15, 2022 by the right navigation camera on Curiosity, shows the rocky and hilly terrain directly ahead of the rover’s present course. In the far distance in the center left can faintly be seen the lower flanks of Mount Sharp itself. The dust in the winter air acts to partly obscure those distant slopes.

The overview map to the right shows us what we are looking at. The yellow lines are my rough guess at the terrain covered by the panorama. The blue dot marks Curiosity’s present position. The red dotted line the rover’s original planned route. The white arrows indicate one of the more interesting upcoming geological features, dubbed by scientists the “marker horizon,” a distinct layer found in many places on the flanks of Mount Sharp.

The green dot marks the approximate location of a recurring slope lineae, a place where the cliff is seasonally darkened by a streak that appears each spring and then fades.

The navigation panorama taken on May 15th also included four more shots covering terrain to the southwest, so what we see above is not necessarily where the rover is heading. The eventual goal is to get back to that red dotted line, but how the rover does so is apparently still being discussed by the science team. It appears they are trying to decide whether to head west again to reach Gediz Vallis Ridge, or instead cut south heading directly for Gediz Vallis.

Either way, that teethlike row of boulders in the near foreground is certainly impressive.

Curiosity climbing out of Gordon Notch hollow

Panorama showing the upcoming steep climb
Click for full image. For original images go here, here, here, here, and here.

Overview map
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Cool image time! The panorama above was created from five photos taken by Curiosity’s right navigation camera on May 4, 2022 as the rover worked its way upward out of Gordon Notch Hollow, the small valley it had left when it attempted to cross the Greenheugh Pediment to the west and was forced to retreat back into when engineers found the rough terrain on the pediment too much for the rover’s wheels.

The overview map to the right provides context. The blue dot marks Curiosity’s present position on Mars, on its 3,465 Sol since landing. The yellow lines mark the area viewed in the panorama, taken two Sols earlier. The red dotted line marks the original planned route, now abandoned. The white arrows indicate one of the more interesting upcoming geological features, dubbed by scientists the “marker horizon,” a distinct layer found in many places on the flanks of Mount Sharp.

On the panorama above the red dotted line is my guess as to the planned route out of Gordon Notch Hollow.
According to the science team’s most recent update on May 4th:
» Read more

As Curiosity retreats from rough country, scientists look at the future geology it will see

Overview map
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Cool image time! For the past two weeks the Curiosity science team has been gingerly and slowing backing the rover off from the very rough terrain of the Greenheugh pediment, as shown on the overview map to the right. The blue dot indicates Curiosity’s present position, with the red dotted line marking its original planned route, now abandoned.

The main question remains: Where to go next? At this point the science team is still debating their exact path forward. As Catherine Weitz of the Planetary Science Institute explained to me in an email today,

The Curiosity team is still working out the details. Maybe in another month or so the new route will be finalized so stay tuned.

No matter what route they eventually choose, the white arrows mark one of the more interesting upcoming geological features that the scientists very much intend Curiosity to reach. In a paper published at the end of March in which Weitz was the lead author, they describe this “marker horizon” as follows:
» Read more

Curiosity retreating from Greenheugh Pediment

Overview map
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Because of the incredible roughness of the ground on the Greenheugh Pediment, the science team for the rover Curiosity has decided to make a major change in their route. Rather than continue their traverse across this terrain, as planned for years, they have decided to back off in order to protect Curiosity’s dinged wheels, and find a more friendly route up Mount Sharp.

“It was obvious from Curiosity’s photos that this would not be good for our wheels,” said Curiosity Project Manager Megan Lin of NASA’s Jet Propulsion Laboratory in Southern California, which leads the mission. “It would be slow going, and we wouldn’t have been able to implement rover-driving best practices.”

The gator-back rocks aren’t impassable – they just wouldn’t have been worth crossing, considering how difficult the path would be and how much they would age the rover’s wheels.

So the mission is mapping out a new course for the rover as it continues to explore Mount Sharp, a 3.4-mile-tall (5.5-kilometer-tall) mountain that Curiosity has been ascending since 2014. As it climbs, Curiosity is able to study different sedimentary layers that were shaped by water billions of years ago. These layers help scientists understand whether microscopic life could have survived in the ancient Martian environment.

The plan is to retrace the rover’s path back through Gordon Notch and then head uphill though another gap that will take it directly onto the next sedimentary layer, dubbed the sulfate unit. On the overview map above, the red dotted line shows the long-planned route. The yellow lines indicate the area seen in the panorama I posted on April 6th, when Curiosity was at its farthest into the pediment. The blue dot marks Curiosity’s position two days ago. You can see that it has retreated backwards.

This change means the scientists will likely not get a close look at Gediz Vallis Ridge. However, it also means the rover will likely reach Gediz Vallis much sooner that previously planned.

Curiosity’s upcoming rough terrain

Curiosity's view looking west on April 5, 2022 (Sol 3435)Click for high resolution. For original images go here, here, here, and here.

Overview map
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Cool image time! The panorama above, created by me from four photos taken by Curiosity’s right navigation camera on April 5, 2022, reveal much about the alien world of Mars that the rover is exploring. The red dotted line indicates approximately the rover’s upcoming route.

First there is the rough surface of the Greenheugh Pediment, the sloping plateau that Curiosity is presently traversing. Called “gater-back terrain” by the science team, this broken surface apparently is sandstone that was originally a dune field that in the past was periodically washed by water runoff and later hardened into this structurally weak rock.

Second, I have orientated the images so that the rim of Gale Crater, approximately 25 miles away, is horizontal. By doing so, we can see the upward slope of the Greenheugh Pediment. Curiosity is on a tilted surface, and while it will be traversing along a contour line as it heads west towards Gediz Vallis Ridge about 1,000 feet away, when it turns left and heads uphill, the climb will be steady and steep, as it has now been for the past year since the rover entered the mountains at the foot of Mount Sharp.

Taken together, these details indicate why Curiosity has moved very slowly in recent weeks, as shown by the white dots in the overview map to the right. The blue dot marks Curiosity’s present location, with the yellow lines indicate the approximate view in the panorama above.

Traversing the pediment carries real risk to the rover. Though its somewhat dinged wheels have held up well during this last year of traveling in these rough mountains, at any point the severe roughness here could damage one or more wheels significantly, even putting one or more out of commission. The rover team is traveling carefully to avoid this, but these factors illustrate a possible end for the rover, though hopefully still years away.

Curiosity presently traveling over broken sandstone from an ancient dune field

Gator-back terrain on Mars
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According to a new paper, scientists now think that the rough and broken cap layer of the Greenheugh pediment that Curiosity is presently traveling across was originally a dune field periodically washed by water runoff, which with time eventually hardened into sandstone.

That broken terrain, dubbed “gator-back terrain” by the Curiosity science team, is shown clearly in the image to the right, taken on March 20, 2022. From the paper’s abstract:

The Greenheugh pediment is capped by a unit of broadly uniform thickness which represents the remains of the Stimson dune field that existed <2.5 Ga (mid- to late-Hesperian). ChemCam geochemical data shows that the sands deposited at the Greenheugh capping unit were sourced from a nearby olivine-rich unit. Surface waters then cemented the windblown sand deposits, ponding at the unconformity with the underlying mudstone unit, creating concretions towards the base. Episodes of groundwater circulation did not affect the rocks at Greenheugh as much as they did at other Stimson localities with the exception of acid-sulfate alteration that occurred along the unconformity. These results suggest that the ancient Stimson dune field was a dynamic environment, incorporating grains from the surrounding geological units on Mt Sharp. Furthermore, liquid water was stable at the surface in the Hesperian and was available for multiple diagenetic events along bedrock weaknesses.

In other words, material from Mount Sharp formed the dune fields, all of which were reshaped by groundwater circulation, with the dunes higher on the mountain seeing less groundwater.

The biggest uncertainty of these findings is explaining how surface liquid water could exist on Mars. Scientists have yet to develop an accepted model that would allow it. Another possibility would be the recent data that suggests Gale Crater was filled with glaciers. If so, scientists would need to figure out how the interaction of a Martian glacier might have geologically changed those dunes in a manner similar to groundwater.

Curiosity’s coming travels across the rocky Greenheugh Pediment

Curiosity's view west on February 21, 2022 (Sol 3393)
Click for full resolution panorama. Original images can be found here, here, and here.

Overview map
Click for interactive map.

Curiosity, having successfully climbed up and out of Gordon Notch, was able to aim its navigation cameras forward yesterday and get its first views from this position across the very rocky Greenheugh Pediment to its next major goal, Gediz Vallis Ridge. The panorama above, taken by the rover’s right navigation camera, shows this view. The ridge is about 1,500 feet away, at its closest point. The rim of Gale Crater, barely visible in the haze, is about 20-30 miles away.

The overview map to the right indicates the area covered in this panorama by the yellow lines. The red dotted line indicates Curiosity’s planned future route.

Curiosity’s first view of the pediment was made in March 2020, from a point on its northern border, just beyond the top edge of the map. The panorama taken then showed what appeared to be a very treacherous and rough surface, possibly too rough for Curiosity to traverse.

According to the science team’s most recent update from before the holiday weekend, the plan had been to spend February 19-20 studying the ground, then drive a short distance yesterday to get a better view ahead.

This will give us a good vantage point to look into the valley ahead and try to scope out our future route. … We chose to drive about 10m total, in order to get the rover oriented at a good heading and parked in a good spot. We expect a similarly beautiful view from our post-drive imaging.

That view is the panorama above. Though still very rough, the ground ahead appears far more traversable than the surface seen in 2020.

Curiosity looks out across the mountains

Curiosity panorama, Sol 3387, February 15, 2022
Click for high resolution. Original images found here and here.

Overview map
Click for interactive map.

Cool image time! The mosaic above, created from two photos taken by Curiosity’s left navigation camera and downloaded from the rover today, looks to the southeast across the small rocky valley the rover has been traversing for the past two months towards Mount Sharp.

The rover had entered this valley through the nearest gap on the left, then traveled uphill from the left to the right until it had passed behind the nearest dark ridge on the right. It then retreated and turned left, starting uphill through Gordon Notch, as shown in the overview map to the right.

On the overview, the white line marks Curiosity’s past travels, with red dotted line indicating its planned future route. The yellow lines indicate the approximate view in the panorama above.

For scale, Navarro Mountain is about 450 feet tall. The actual peak of Mount Sharp is blocked by the white front range to the left. The rover is presently still 12,600 feet below that peak, which sits to the southeast about 35 miles away.

Alien and barren Mars

Curiosity's view looking to northeast, sol 3376 (February 4, 2022)
Click for full resolution. Click here, here, and here for original images.

Overview map
Click for interactive map.

Cool image time! The panorama above was created from three photos downloaded today from Curiosity’s right navigation camera. It looks to the northeast of the rover, out across Gale Crater. The crater floor is about 1,750 feet lower.

This is dust season on Mars, which explains the thick haze in the crater. About 25 miles away the crater rim can be faintly seen through the dust haze as a mountain chain. If you look at the full resolution panorama you can see several buttes on the crater floor barely visible through that haze.

The map to the right gives the context. Curiosity’s present location is indicated by the yellow dot, with the yellow lines indicating the area covered by the panorama. The red dotted line indicates the rover’s future planned route.

For the last few weeks Curiosity has been working nestled to the base of a small butte the science team has dubbed “The Prow”, studying its numerous thin layers. I featured the Prow in this January 11th post, though at the time I overestimated its size, which is only about ten feet high. The butte is especially fascinating in that its top layers overhang outward in an unbelievable manner.

The rover is now about to move on, though where must still be decided by the science team. Based on their most recent update it appears they are not ready to leave this barren rocky hollow surrounded with many-layered buttes, and will take the rover to another.

Carbon isotope signature detected in Curiosity data suggests possible ancient life, or not

The uncertainty of science: In reviewing data from Curiosity, scientists have detected a faint enrichment on ridge tops in Gale Crater of the carbon isotope carbon-12, normally associated with life on Earth because it is easier for life to process than the heavier carbon-13 isotope.

In order to explain this enrichment, the scientists have concocted several complicated explanations, all of which seem unlikely because of their complexity. The explanations that include life require a series several precise steps to get the enrichment limited to only high ridges. Another that doesn’t involve life requires the solar system to pass through an interstellar cloud.

One proposed explanation is simpler however, and does not require ancient microbes or interstellar clouds.

More prosaically, a few studies suggest UV rays can generate the signal without help from biology at all. UV can react with carbon dioxide—which makes up 96% of the martian atmosphere—to produce carbon monoxide that is enriched in carbon-12. Yuichiro Ueno, a planetary scientist at the Tokyo Institute of Technology, says he has recently confirmed the process can occur in unpublished lab results. “The reported carbon isotope ratios are exactly what I have expected,” he says.

Though this explanation must explain why they have seen the enrichment only at high points, it is straight forward and fits all the present data we presently have of Mars

All in all, the data is tantalizing but hardly a indicator that Mars once had life. There is too much uncertainty. We do not yet know enough about Mars’ geological and climate history to come to any consensus on an explanation.

A butte on Mars

A butte on Mars
Click for full photograph.

Cool image time! Because the Martian geology inside the enclosed stone valley beyond Maria Gordon notch is so complex and exposed, the Curiosity science team is spending a lot of time there. As noted in their January 7th update:

[W]e are marvelling at the landscape in front of us, which is very diverse, both in the rover workspace and in the walls around us. It’s a feast for our stratigraphers (those who research the succession in which rocks were deposited and deduce the geologic history of the area from this). We are all looking forward to the story they will piece together when they’ve had a bit of time to think!

The image to the right, cropped and reduced to post here, was taken by the rover’s high resolution camera on December 18th, soon after it entered this stone valley and was part of scan covering both this butte as well as a nearby cliff. I had previously featured a close-up of the top of this butte and its incredible overhang on December 20, 2021. This image however shows the whole butte, which I estimate to be about 30 to 40 feet high is about 10 feet high.

Not only does the butte illustrate well the alien nature of this stark and barren Martian terrain, so does all the terrain surrounding it. The surface everywhere is nothing but pavement stones of all sizes. Once again, there is no life, something you practically never see on Earth.

The barren rocky terrain in the mountains of Gale Crater

Curiosity's view looking south towards Mt Sharp, Sol 3333, December 21, 2021
Click for full resolution image. Original photos can be found here, here, here, here, and here.

Overview map
Click for interactive map.

Cool image time! Curiosity yesterday used its navigation cameras to take a panorama of the view inside Maria Gordon Notch. The mosaic above, created from five images taken by the right navigation camera, shows the view looking south and uphill towards Mount Sharp. The heights of the nearest four hills are likely ranging from 30 to 100 feet.

The red dotted line indicates the planned route out of Gordon Notch and up onto the Greenheugh Pediment. If you click on the panorama to look at the full resolution version, you will see that the exit route looks extemely rough, possibly too rough for Curiosity to handle. How the science team handles this issue will be fascinating to watch in the coming weeks.

The map to the right gives us an overview. The white line is Curiosity’s actual travels. The red dotted line marks the planned route. The yellow lines indicate the area covered by the panorama above.

The most striking feature of this Martian terrain is its stark barrenness. All one can see in all directions are rocks and inanimate geology. There is no life, none at all. On Earth it is practically impossible to find any mountainous spot as barren as this, even in the most extreme and hostile environments.

As I’ve said before, Mars is strange, Mars is wonderful, and above all, Mars is alien.

Curiosity looks back at its entire journey

Curiosity looking back across Gale Crater
Click for high resolution mosaic. Original images here, here, here, and here.

Wide overview map
Click for interactive map.

Cool image time! The mosaic above was created from four photos taken by Curiosity’s left navigation camera on December 12, 2021, just after the rover had moved into Maria Gordon Notch. The view is to the north, looking back at the rover’s journey climbing up the floor of Gale Crater into the foothills of Mount Sharp. The rim of Gale Crater can be seen about 25 to 30 miles away.

The cliff in shadow on the left is about 40 feet high. The cliff in sunlight on the right is between 30 to 60 feet high, depending on where you measure.

The overview map to the right shows Curiosity’s entire journey, with the yellow lines indicating the approximate area covered by the mosaic above. All told the rover has climbed about 1,700 feet since it landed. While much of the rover’s route is blocked from our view by the cliffs on left, the nearest sand dune sea in the center of the mosaic is the one that the rover circled around from January 2021 to June 2021.
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Curiosity takes a close look at a Martian cliff

A cliff of Mars
Click for full resolution. Original images here and here.

Curiosity has now moved up and into Maria Gordon Notch, a gap in the mountains of Gale Crater that is about forty feet wide, with a 40-foot-high cliff on its western side and a 30 to 60 foot cliff on its eastern side.

The mosaic above, created from two navigation camera images, looks up at the top half of that western cliff. Note the many many layers, each one of which records some climate or volcanic event in Mars’ geological history. The Mars we see today took a long time and many events to become what it is. Such layers however have not been seen everywhere by Curiosity. Compare for example this layered cliff with the massive outcrop dubbed Siccar Point and looked at closely by the rover in October. In that outcrop the layers were either non-existent, or merged together during some subsequent geological process.

Note also the pond of sand/dust at the center-bottom, nestled in a hollow but sitting almost vertical. That the dust can maintain itself at such an angle illustrates Mars’ lighter gravity, about 39% of Earth’s, which in turn allows for a much steeper angle of repose. That lighter gravity also allows for some sections of rock to stick out more precariously than possible on Earth.

As Curiosity moves through the notch in the next few days, more such cool pictures will become available, and I shall post them.

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